Re: [PATCH] PCI: vmd: Fix secondary bus reset for Intel bridges

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Oct 06, 2022 at 11:26:08AM -0700, Munoz Ruiz, Francisco wrote:
> Hi,
> 
> Please let me know if something else is needed.

We're in the merge window now, so it's too late for v6.1, but we'll
start merging v6.2 changes about Oct 17.

> On 9/26/2022 2:07 PM, Jonathan Derrick wrote:
> > On 9/23/2022 2:37 PM, francisco.munoz.ruiz@linux.intel.com wrote:
> > > From: Francisco Munoz <francisco.munoz.ruiz@linux.intel.com>
> > > 
> > > The reset was never applied in the current implementation because Intel
> > > Bridges owned by VMD are parentless. Internally, the reset API applies
> > > a reset to the parent of the pci device supplied as argument, but in this
> > > case it failed because there wasn't a parent. This change feeds a child
> > > device of an Intel Bridge to the reset API and internally the reset is
> > > applied to its parent.
> > > 
> > > Signed-off-by: Francisco Munoz <francisco.munoz.ruiz@linux.intel.com>
> > > Reviewed-by: Nirmal Patel <nirmal.patel@linux.intel.com>
> > Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
> > 
> > > ---
> > >   drivers/pci/controller/vmd.c | 12 ++++++++++--
> > >   1 file changed, 10 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> > > index e06e9f4fc50f..34d6ba675440 100644
> > > --- a/drivers/pci/controller/vmd.c
> > > +++ b/drivers/pci/controller/vmd.c
> > > @@ -859,8 +859,16 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> > >   	pci_scan_child_bus(vmd->bus);
> > >   	vmd_domain_reset(vmd);
> > > -	list_for_each_entry(child, &vmd->bus->children, node)
> > > -		pci_reset_bus(child->self);
> > > +
> > > +	list_for_each_entry(child, &vmd->bus->children, node) {
> > > +		if (!list_empty(&child->devices)) {
> > > +			pci_reset_bus(list_first_entry(&child->devices,
> > > +						       struct pci_dev,
> > > +						       bus_list));
> > > +			break;
> > > +		}
> > > +	}
> > > +
> > >   	pci_assign_unassigned_bus_resources(vmd->bus);
> > >   	/*